glibc/sysdeps/alpha/alphaev67/strlen.S
2000-12-08 17:20:12 +00:00

62 lines
1.7 KiB
ArmAsm

/* Copyright (C) 2000 Free Software Foundation, Inc.
Contributed by David Mosberger (davidm@cs.arizona.edu).
EV67 optimized by Rick Gorton <rick.gorton@alpha-processor.com>.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Library General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Library General Public License for more details.
You should have received a copy of the GNU Library General Public
License along with the GNU C Library; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
/* Finds length of a 0-terminated string. */
#include <sysdep.h>
.arch ev6
.set noreorder
.set noat
ENTRY(strlen)
#ifdef PROF
ldgp gp, 0(pv)
lda AT, _mcount
jsr AT, (AT), _mcount
.prologue 1
#else
.prologue 0
#endif
ldq_u $1, 0($16) # L : load first quadword ($16 may be misaligned)
lda $2, -1($31) # E :
insqh $2, $16, $2 # U :
andnot $16, 7, $0 # E :
or $2, $1, $1 # E :
cmpbge $31, $1, $2 # E : $2 <- bitmask: bit i == 1 <==> i-th byte == 0
nop # E :
bne $2, $found # U :
$loop: ldq $1, 8($0) # L :
addq $0, 8, $0 # E : addr += 8
cmpbge $31, $1, $2 # E :
beq $2, $loop # U :
$found:
cttz $2, $3 # U0 :
addq $0, $3, $0 # E :
subq $0, $16, $0 # E :
ret $31, ($26) # L0 :
END(strlen)